Albert Barnes Commentary Ezra 7:21

"And I, even I Artaxerxes the king, do make a decree to all the treasurers that are beyond the River, that whatsoever Ezra the priest, the scribe of the law of the God of heaven, shall require of you, it be done with all diligence," — Ezra 7:21 (ASV)

All the treasurers - The Persian system of taxing the provinces through the satraps involved the establishment in each province of at least one local treasury.